What does bondstone mean?
A bondstone is a stone built into a wall specifically to bind together its separate vertical layers, known as wythes. In traditional solid-wall construction, a wall's outer face and inner backing could otherwise behave as two independent skins; bondstones — sometimes called through stones, perpends, or binding stones — are laid at regular intervals so they pass through the entire thickness of the wall, stitching the layers into a single structural unit. The term belongs chiefly to the vocabulary of masonry, architecture, and building conservation, appearing in British specifications and heritage guidance more often than in casual conversation. Bondstones are typically placed in horizontal courses and are often required by conservation standards to match the surrounding material. Though obscure to most readers, the word captures a quiet truth of traditional building: much of a wall's strength depends on elements completely hidden from view, working unseen for centuries.
nounA masonry term for a stone that ties together the two outer layers (wythes) of a wall, passing through or anchoring into both so the wall acts as a single structural unit.
- A stone laid across the full thickness (or deep into) a wall to bind its facing and backing layers structurally together.
"The surveyor noted that several bondstones had been removed from the garden wall, leaving the facing dangerously loose."
"Traditional brick walls were strengthened at intervals with a bondstone running right through from front to back."
"Conservation guidelines require that any replacement bondstone be of matching stone and laid on the same bedding course."
Regular plural; typically used when describing walls containing multiple such stones at intervals.
"The restoration crew replaced six weathered bondstones along the boundary wall."
Every sturdy old brick wall owes its strength to hidden stones you'll never see — bondstones, the invisible stitches holding two faces of masonry into one wall.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of bondstone
Bondstone is a straightforward English compound formed from 'bond' — in its masonry sense of the patterned interlocking arrangement of bricks or stones — plus 'stone'. The word arose within the English building trades, likely during the early modern period, as masons needed a precise term for stones laid transversely to tie a wall's faces together. It shares its first element with related trade vocabulary such as 'bond' courses in brickwork, and is unrelated to financial bonds despite any modern association.
How bondstone is actually used
A technical term used mainly in masonry, building conservation, architecture, and heritage contexts; rarely encountered in everyday speech. It appears most often in British building regulations and conservation literature, though it is understood in American construction practice as well.
Easily confused with bondstone
A keystone is the central wedge-shaped stone at the crown of an arch, whereas a bondstone runs through the thickness of a wall to tie its layers together.